по идее, должен быть

is supposed to be

→ по
phrase Rare #48,334
is supposed to be Expresses an expectation or assumption that someone or something should be in a particular place or state. По идее means “in theory” or “presumably,” while должен быть changes according to the subject’s gender and number.
RU: Сегодня он, по идее, должен быть дома.
EN: He is supposed to be home today.

Сегодня он, по идее, должен быть дома.

Today, in theory, he should be at home.

Я, по идее, должен быть в Бостоне.

I should be in Boston, in theory.

Ты, по идее, должен быть сейчас там.

You’re supposed to be there right now.

Том, по идее, должен быть сегодня здесь.

Tom is supposed to be here today.